/Engine/Source/Runtime/Engine/Classes/Materials/MaterialExpressionStaticComponentMaskParameter.h
bool SetParameterValue ( [FName](API\Runtime\Core\UObject\FName) InParameterName, bool InR, bool InG, bool InB, bool InA, [FGuid](API\Runtime\Core\Misc\FGuid) InExpressionGuid, EMaterialExpressionSetParameterValueFlags Flags )